The new Defender (L663) is a fantastic vehicle, but its smart key system has caught a lot of owners out. The ‘Smart Key Not Recognised’ or ‘No Key Detected’ warning appears on countless owner forums, and it’s usually one of a handful of specific causes.
Here’s what’s actually going on, and how to fix it.
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Why the L663 Defender Specifically Has Key Detection Issues
The L663 uses the new InControl OS infotainment platform with a refreshed smart entry module. It’s more sensitive to low fob battery voltage, RF interference, and BCM desync than older Land Rover platforms.
1. CR2032 battery weaker than the system tolerates
L663 firmware demands a minimum fob battery voltage. Even a battery that still works in older Defenders may be flagged as too weak in the L663. Replace at the first sign of intermittent recognition.
2. Phone interference (the L663-specific issue)
The L663’s keyless system overlaps with some 5G phone frequencies. Carrying your phone in the same pocket as the fob can cause signal masking. Separating them by a few inches resolves it.
3. Key in ‘sleep mode’ after no use
L663 fobs go into deep-sleep after extended inactivity. The first press after a long gap may not register. Press twice or hold the unlock button for 2 seconds.
4. BCM desync after software update
If your Defender has had an OTA software update or workshop visit recently, the keys can desync from the BCM. The car drives but throws ‘Key Not Recognised’ intermittently.
5. Faulty interior antenna (rare but happens)
L663s have a redundant antenna setup, but if the primary antenna behind the start button fails, you’ll see this warning when one specific person sits in the driver’s seat with the fob in their pocket.
AJ Auto tip: If the warning only appears when the fob is in your back pocket but not when you place it in the centre console cup-holder, the antenna pickup is weak, usually the fob battery, occasionally the antenna itself.
The Fix Process
- Replace fob battery (CR2032)
- Try the spare key
- Test with the phone in another pocket
- If still failing, OBD diagnostic and BCM resync
What It Costs
- L663 fob battery: £25 fitted
- BCM resync (mobile): £180
- L663 replacement smart key: From £450 (newer keys are more expensive than older Defender keys)
Stuck Without a Key?
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Why Choose AJ Auto
We are a JLR-only specialist. We do not dabble in keys for 50 different brands: we live and breathe Jaguar, Land Rover, and Range Rover. 15+ years of experience, fully insured, DBS-checked, 12-month warranty on every key, and we come to you anywhere in the UK with same-day service available.
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Frequently Asked Questions
Why does my Defender L663 say "Key Not Found"?+
How do I start a Defender L663 when it says Key Not Detected?+
Can a software update fix Defender L663 key recognition issues?+
What is the Defender L663 key pairing process?+
How much does a Defender L663 replacement key cost?+
When to go to a dealer instead
If your vehicle is still under JLR factory warranty and the fault is covered, take it to a dealer. Warranty repairs are free and no specialist can match that. If you need a recall fix, the dealer is the right call. Outside of those two situations, a mobile JLR specialist will be faster, cheaper, and will attend at your location.